Nanoparticles are microscopic substances that act the same as their larger counterparts, and have been used on some level since the 9th Century (according to archaeological records) by pottery artisans. They are essentially the same as the larger units, however, the physical and optical properties of the nanoparticles can change. For example, nanoparticles can have different melting points, or exhibit different colors than the larger particles. The nanoparticles have a very high surface to volume ratio, which allows the particles to adhere to surfaces that the larger particles could not. However, this also makes the particles much more reactive. They are also able to pass through the cell membranes of organisms, but very little research has been done on exactly how they interact with biological systems. Nanoparticles are commonly used in sunscreens to make them clearer instead of chalky, on razors to keep them sharp, in hospitals to coat medical equipment and surfaces with antibacterial properties, on clothing to repel dirt, on golf balls to improve their flight path and distance, and more and more in our food system. Nanoceramics can work to reduce the friction on surfaces such as frying pans and pots, and nanosilver is used in food packaging due to its antibacterial properties. Nowadays, though, nanotechnology can also be found in the very foods and nutritional supplements themselves.
It is difficult to create a list of foods that contain nanoparticles because the U.S. Food and Drug Administration (FDA) does not require labeling them, nor do they keep track of which foods they can be found in. The FDA has placed nanoparticles within the category, “Generally Recognized As Safe” because they believe they are just tiny forms of the larger substances, which are already regulated. So, nanoparticles are now found in many foods, such as those that contain caramelized sugars like corn flakes and bread. Titanium dioxide in its nano form is added to food products to make them whiter, such as vanilla frosting, gum, pudding, Pop-Tarts, coffee creamer, and powdered donuts. Clearly, we are meant to be ingesting this nanoparticle (whether we ought to be is another debate), since it is found inside the food itself. But there are other nanoparticles that are unintentionally entering our foods, primarily through packaging. Nanoclay is used to line plastic soda bottles, nanoaluminum is used on aluminum foil to make it reflect heat and prevent foods from sticking to it, and nanosilver is used as previously mentioned. And there is evidence that these nanoparticles do not stay put; they shed ions, which can then be consumed by us. What happens after that is still up for debate, and severely lacking in research.
The American Society of Safety Engineers believes that ingested nanoparticles can be absorbed in our small intestines and enter our blood stream, moving throughout our bodies. They believe that nanoparticles can accumulate in various organs, and can potentially disrupt or impair biological or metabolic processes, and weaken the immune system. A study conducted by Cornell University found surprising results when exposing chickens to polystyrene nanoparticles (which are approved for human consumption). When the chickens were exposed to the polystyrene nanoparticles for a short period of time in high amounts, it blocked the birds’ abilities to absorb iron. However, when the chicken was exposed to small doses of the nanoparticles for a long period of time, it increased the bird’s rate of iron absorption. The tricky part is that it’s difficult to say if this would transfer to humans, and it also sheds no light on other nanoparticles, as they all act completely differently. Each one needs to be tested individually, and then – optimistically – tested synergistically to determine if our bodies will react differently if we absorb a variety of these nanoparticles, which is far more realistic. However, the onus is on the general public to discover where the nanoparticles are, as it is voluntary for companies to label or identify their products that contain them, and the FDA and EPA are not required (nor given funding) to monitor them. (Although in my opinion, the companies should prove a product or substance’s safety, not require the government to prove its innocence or guilt.)
Universities in other countries have conducted studies of nanoparticle ingestion. In Holland, researchers studied rats exposed to surfaces and products with nanosilica coating over ten weeks. They observed that the nanosilica was absorbed into the rats’ bodies and the levels became toxic in the rats’ livers. It is not only adverse health effects that are being researched. In the U.S., researchers at UMass Amherst are working on nano-vitamins, nano-antioxidants, and nano-Omega 3 Fatty Acids. They believe our bodies will more readily absorb these all-natural nanoparticles, more so than the current vitamins and minerals that fortify many foods we eat today. However, there is a risk of making such concentrated doses, as it would great increase the chance for toxicity to occur. However, these are all still in the development phase, and still a long ways from our foods. For now. But there are nanoparticles in our food system, and they are likely migrating into our biological systems. Whether or not they are harmful is still unknown. It is likely that this issue could explode, much like the GMO issue if precautionary actions are not taken and open dialogue not engaged. Only time will tell, but in the mean time, you can keep informed, ask questions, and buy local food!